Bidirectional no-back power transmission



Jan. 4, 1949. w. c. STARKEY 2,458,441

BI-DIRECTIONAL NO-BACK POWER TRANSMISSION 1 Filed July 2, 1945 2 Sheets-Sheet 2 Patented jan. 4,

ilNlTED STATES IATENT OFFICE BIDIRECTIONAL NO-BACK POWER TRANSMISSION William Carleton Starkey, Indianapolis, Ind. Application July 2, 1945, Serial N 0. 602,788

Claims.

This invention relates to a bi-directional no- Tback power transmission such as to permit a driving member to drive a driven member in .either direction, but prevent the driven member from driving the driving member, reference being had to myapplication for Letters Patent, Serial No. 491,301, filed June 18, 1943, entitled Anti-kickback clutch, now Patent No..2,421,814, dated June 10, 19.47..

Heretofore, in devices of this character, a single helical spring has been employed serving togbe expanded into frictional locking engagement With a fixed pocket to lock the driven member against rotation when a torque load is applied thereto, while, on the other hand, upon the torque load being applied to the driving member it will first engage one or the other end portion of the spring to move it in a declutching direction whereby it is wrapped down out of frictional locking engagement with the fixed pocket to permit relative rotation of the driving and driven member. In such structures embodying the single clutch spring, there has been of necessity a certain free play or back lash when torque is applied to the driven ,.member because it must rotate slightly before rengaging one or the other end of the spring to ;move it in a direction to expand it into frictional locking engagement with the fixed pocket.

It is the purpose of this invention to provide ra bi-directional no-back power transmission, :sometimes referred to as an anti-kickback 4011112011, of such construction that the driven member will be prevented from having the slightrest movement or back lash when torque load is applied thereto. It thereby becomes a'positive and immediate lock against counter drive without any play in the reverse drive direction. This is accomplished by employing dual clutch springs, each having positive connection with the driven member and normally in positive locking engagement with the fixed or stationary pocket, whereby the driven member is at all times'positively locked by both clutch springs against rotationwhen a torque load is applied thereto. Back lash or slight rotative movement of the driven member until such time as it acts to expand the spring into positive locking engagement with the fixed pocket, as heretofore, is thereby eliminated.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims: 1

Fig. 1 is a central vertical section through the power transmission showing the drivi-ng member in elevation but with'portions thereof in. section.

Fig. 2'is a central vertical section taken on the line 2-2 of Fig. 1.

Fig. 3 is a central vertical section taken on the line 33 of Fig. 1.

Fig. 4 is the same as Fig. 1, showing a modification thereof.

Fig. 5 is a section taken on the line 5-5 Fig. 4.

Fig. 6 is the same as Fig. 1, showing a further modification thereof.

In the drawings there is shown a driving member IE1 and a, driven member ll. The driving member comprises a shaft telescoped and r.otatably supported within a tubular sleeve portion of the driven member. Rigidly keyed to the sleeve portion of the driven member there is a pair of spaced pockets l2 and 13 having internal clutch surfaces indicated at M and 'l5, respectively. Intermediate said pockets l2 and 13 there is a stationary or fixed member or support 16 having a central annular bearing ll within which the sleeve portion of the driven memberis rotatably supported. Each end portion of the stationary member i-sformed with oppositely and outwardly extending fixed pockets I8 and I9 for'providing internal cylindrical clutch surfaces.

Mounted Within the pockets l2 and 18 there is a braking element comprising a helical spring ZEIWith a corresponding spring 2| mounted within the pockets l3, l9. Said clutch springs are wound slightly over size to positively engage the clutch surfaces of said pockets respectively under spring tension. One end portion'of the spring 20 extends in or is keyed to the pocket 12, as indicated at 22. The opposite end of the spring 20 extends downwardly to provide a. projection or toe 23. Correspondingly, the spring 2| has one end anchored to the pocket l3 at 24 and the other end extends inwardly to provide a projection 25. The projections 23, 25 lie adjacent opposite sides of the central bearing portion I! of the stationary member.

The driving shaft it) carries a pair of energlzing pins 26 and 21 extending radially therefrom and in axial alignment with each other. Said pins protrude through the elongated slots 28 respectively provided in the sleeve portion of the driven member H. The pin 26 extends in position to engage the projection 23 of spring 26. The pin 21 extends into position to engage the projection 25 of spring 2|. The outer ends of said pins are slightly spaced from .the inner surface of the respective clutch springs.

The shaft H3 is provided with a driving key 29 extending into a keyway 30 provided in-the sleeve portion of the driven member I l. The clearance between the key 29 and keyway 30 is less than the clearance between the energizing pins 26, 21 and their respective slots 28 so that said energizing pins have free play relative to the sleeve portion of the driven member without interfering with the driving connection afforded by the key 29 between the driving and driven members. Thus, the shaft II! will drive the shaft ll through the key 29 n th rdi sei e th et int rferes? between the energizing pins and the driven member.

The shaft I is provided with a bore 3| to receive a detent spring 32 operatinggipqniiihfirtlelifim ball 33. The sleeve portion of the driven member H is provided with a detent seat 3 4 for,re cei vi ng the ball 33. The bore and seat ar'so'align''d relative to each other that theldetenhballkwill yieldingly interlock the shafts ID and II in ,gem tralized position with the key 29 centrailiofthe keyway 30 and the energizing pins c-entrallyof the recesses through which theyeigtendTai'id in proper relation to the projections 23:25 of the respective clutch springs. it f0 Joe noted that h ke 3 i seat .e b i -.&? i keywa'y a greater distan-ce tharf'theene fgizing p g re ewe -flew iher 'qiq ti e p $131.5 l t springs so that said projections will be engaged .b the tentati en a ing tr e ebe e i t driving keyis brought into drivingeng agen i ent withi t tliewev In .jq et Pa e Lie ee 1 wa s ated lq kwie a h efi Am s sien 'r i iiists e es t trie e t qefite -i a ,2 t wra said ,sriesd wnlegtofeeem n 'i ith t placke Qap i it by gire th s ri fre it lr ri e .i pe n ge c n ytha sed eieer-' i Bu e a k 2 wi h i -eshiet re s m Wlth hi theoverrunning or wrap clow dirction'sma {t I free it from it grieiieeehlefi? re gs w th th -seem J33- iEhs il -s 3L1." w l th t ter e eie t 4 Fee yte 'etie f e .a esae islrite islemeet ieeletiv gt fie fite me ib flfithes t sk t i 399.9 re tine .n t teens wrap m dtown-out. o ock-i islensa ementfivheriuponythe drivin key'gze will pejmoveiintq .r v-

n n asem nt iwith eth leeve tnortian 10 ith driven member H. {The sleeve member r wi ll :carry; with; itv thepocket; 4 3 todwhichlone end of spring; 2 l t is anchoredat 24, th us tending; -,to.,wrap

clowns springi2 I p out nofilocki ng engagement inan ov-errnnning. :direction. 'JIhis,..of v.cqurse,t...pe'rmits an overrun .of. both springs relative to .the liked element so astopermit the'drivling action. Upon the driving member l0 beingmrelievediofi itsv driving torque, the detent bal1.33 willwseek' the pocket 1 34 under spring tension to=centerl theidri'vingand driven members in the manner. above described.

-i I will be imparted to said springs through-their end connections 22, 24 in a direction tending to expand one or the other, increase in torque load on the driven member will merely tend to tighten one of said springs in its locking engagement. Therefore, by means of the dual clutch springs being positively anchored to the driven member and normally in looking engagement therewith, no back lash or movement thereof will be pernittedgwhen a ,torque load is applied thereto. For example, iipon a torque load being applied to shaft II in a clockwise direction (Figs. 2 and 3), 'spring 2! would tend to expand, and in a counter- ,olockwise direction spring 20 would tend to expand.

DI the modified form shown in Figs. 4 and 5, thd'rivin'g key'29 and the pins 26, 21 above described are combined into a single energizing and drivi ng key I21 secured to the driving memher [0 in the same relative position as the energizing pins 26, 21 of Fig. 1. This energizingand drivihg'flky vsimilarly extends through an elongates-"$1 5128 iii-the sleeve portion ofthe driven "rfieiiibei; said key isfifree to rotate within the seam portion of thelfixed element .1 1.6, one of the pdckts'of which is indicated {at ts andith'e othiipoket at I-l'8.

I-n operation; 'when .the ,driving element n .is rotated in" a clockwise direction, the key l 21 first engages the projection 25 of spring 2| toreleajse said .'spring, thereaft'er" movinglth'rough the "slot l 2 8-to engage 'and' drive the driven :inember" l l. Upon counterclockwise rotation of .the driving 'rii'iiibn the key.l.2 1 moves into engagement with thfii'rbjtibriflii'of springi20 to Wrap it dQWn 'out df locking engagement, after Whichit pr'oc'e'ed to engage and Ldriv'eithe driven. member. 1 l '{L'liiis in all'respe'cts the-key L21 rcomprisesan energizing means acting .in' precisely the same manner .as ftheienergizin'g means consisting of pins 26, and42-1i to ..\en 'gage.,the, energizinglendi'port'ionss23 25 oft-the vchit'ch springs. [Said key, I21, .threfore, .ac'ts eboth as the "energizing ,and the driving means.

' Asilshotvn in 6, the pockets 21,2 and 2 L3 .are'.integrally-formed, or-,..0ther,wise s ecured to the sl evano tionpfi th drive m m e 4 i aw i precise y the sam man e a th above des ribe pockets t2 .and ,-L3 Qflfjg. '1. ,The iixed element in: th m dification; in lude seate pocke 1? 2. is servin in the am man e a th ,go espendin no t l of th fi e e emen shave mew -1. .iih se ii ehis r e g t? ere crv t iea i to en iremth m i 'i an s. is-.1 i ii lp es ;si ila i i uns fim" if ri t onally lock with th respectivepo'c'kets. The 4 s i -eedse rs r sse 2 .2 11 4 th rfloppose d buter i ee l gi i spt m h i fii end toward 'the' load farjif iijgi'efoiis; as indicated at 35, in the I'nar'i'iir'afndffor thpiirpo'se "as dis- 1 erased inm j ie'tter's Pateri't'NoJ 1,953370, granted April 3,' i'934;""entit ed'rsbni gfeiu chl" S aid clutch sp fl gs ofthjlutg'ih surface of thepo'ckts 'inayTbef knurled instead of: being grooved, in the f'fiianiier aricl 'for -thei 'pui'pose'as difs'closed 'in' "my applicants-serial warezmsvgmea Novembens,

5. 1945, entitled Spring clutch device and method of making the same. In this connection it is to be noted that this construction embodying the dual clutch springs permits of so forming said springs either by grooving or knurling as to permit their respective energizing ends to operate more efiiciently and positively in their locking and releasing action while retaining the maximum surface contact with the load carrying coils. This permits the load carrying end of the clutch spring to be of greater cross section or surface area to carry the peak loads than the energizing ends of the springs, to thereby cut down the overrunning torque while overrunning in their respective pockets upon the driving torque being applied to the driving member. Also in the single spring no-back device, each end of the spring has to serve alternately as the load carrying end and the energizing end. Thus, the energizing end has to carry the peak load when rotated in one direction and still act as a flexible energizing end when rotated in the other direction. By utilizing dual springs, each may have one end particularly designed as a load carrying end and the other end particularly designed as the more sensitive energizing end.

The invention claimed is:

1. In a power transmission, the combination of driving and driven members, one of said mem bers having opposed pockets, a fixed element having opposed pockets matching the afore-mentioned pockets, respectively, and a braking ele ment comprising a helical spring mounted in each pair of matching pockets for locking engagement therewith, each of said springs having one end portion thereof operable by one of said members tending to exert a locking action with said pockets and the other end operable by the other of said members for causing it to release said pockets,

said members being operably engageable with each other to provide an interdriving connection therebetween upon one of said clutch springs being moved out of locking engagement with one of its associated pockets.

2. In a power transmission, the combination of driving and driven members, one of said members having opposed pockets, a fixed element having opposed pockets matching the aforementioned pockets respectively, a braking element comprising a helical spring in each pair of matching pockets normally in looking engagement therewith, each of said springs having one end interlocked in its respective first-mentioned pockets, and means carried by the other of said members operable to engage the opposite end portion of one of said springs according to the direction of rotation for causing it to overrun said fixed element, said means thereafter providing a driving connection between said members.

3. In a power transmission, the combination of driving and driven members, one of said members having opposed pockets, a fixed element having opposed pockets matching the aforementioned pockets, respectively a braking element comprising a helical spring mounted in each pair of matching pockets normally in locking engagement therewith, each of said springs having one end interlocked with said driven member, and means carried by said driving member operable to engage the opposite end portion of one of said springs according to the direction of rotation for causing it to release said fixed element, said means thereafter providing a driving connection between said members.

4. In a power transmission, the combination of iii 6 driving and driven members, one of said members having opposed pockets, a fixed element having opposed pockets matching the aforementioned pockets, respectively a braking element comprising a helical spring mounted in each pair of pockets, respectively a braking element comprising a helical spring mounted in each pair of matching pockets normally in locking engagement therewith, each of said springs having one end interlocked with said driven member, a pair of aligned energizing pins carried by said driving member, one of said pins being positioned to engage the free end portion of one of said clutch springs and the other pin being positioned to engage the free end portion of the other of said springs according to the direction of rotation of said drivin member for causing the engaged spring to release said fixed element, and a lost motion driving connection between said members operable upon said engaged clutch spring being moved out of locking engagement.

6. In a power transmission, the combination of driving and driven members, one of said members having opposed pockets, a fixed element having opposed pockets matching the aforementioned pockets, respectively a braking element comprising a helical spring mounted in each pair of matching pockets normally in looking engagement therewith, each of said springs having one end interlocked with said driven member, and an elongated key extending radially from said driving member for engagement with the free end of one of said springs when rotated in one direction and engagement with the other of said springs when rotated in the opposite direction for causing the engaged spring to release said fixed element, said key being thereafter engageable with said driven member for driving said member upon continued rotation thereof. 7

7. In a power transmission, the combination of driving and driven members, one of said members having opposed pockets, a fixed element having opposed pockets matching the aforementioned pockets, respectively a braking element comprising a helical spring mounted in each pair of matching pockets normally in looking engagement therewith, each of said springs having one end interlocked with said driven member, means carried by said driving member operable to engage the opposite end portion of one of said springs according to the direction of rotation for causing it to release said fixed element, said means thereafter providing a driving connection between said members, and yielding means interengageable between said members for centering them in nondriving relation.

8. In a power transmission, the combination of driving and driven members, one of said members having opposed clutch surfaces, a fixed element having opposed clutch surfaces matching the aforementioned surfaces respectively, a braking to the direction of rotation of said driving member to cause the engaged spring to release said fixed element, a driving key carried by one of said members thereafter engageable with the other of said members for providing a direct drive therebetween, and a sprin pressed detent car,- ried by one of said members engageable with a centering seat provided in the other of said members for centering said pins and key in their inoperative positions.

15. In a power transmission, the combination of means providing a fixed clutch surface, a driving and a driven member, a pair of braking element comprising a helical spring both normally in locking engagement with said surface, one end of each spring secured to the driven member and the opposite end of each spring being free and located on opposite sides of a plane extending radially of the driving shaft, and energizing face.

WILLIAM CARLETON STARKEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,867,643 Ackerman et a1. July 19, 1932 1,997,646 Miller Apr. 16, 1935 2,372,693 Swift Apr. 3, 1945 

